It has long been recognized that there is a normal transcutaneous electric potential associated with mammalian skin (see, e.g., Robert Edelberg, in, The Biophysical Properties of the Skin, Harry Elden(ed.), Chapter 15, Wiley Interscience, 1971). This potential is to a great extent influenced by the presence of sweat glands and hair, and thus the strength of the potential may differ both spatially and temporally on the skin. However, even in nonglandular areas of the skin, there is a fairly strong, measurable current produced across the epidermis, in essence a skin battery. Although most measurements have been conducted on non-human mammals, considerable evidence exists for the same type of battery to exist on human skin as well(Barker et al., Am. J. Physiol. 242: R358-R366, 1982). Such batteries have been known to exist in amphibians, where they apparently serve a function in sodium uptake and appendage regeneration. However, their purpose in a nonaquatic vertebrate was not readily apparent. Based on observations of fairly strong voltage gradients at the margins of wounds, Barker et al. and others have suggested that in mammals the skin currents may be important in the process of wound healing.
Further evidence of the importance of electrical currents in the maintenance of healthy skin has been shown in the successful use of electrotherapy in treatment of skin ulcers. For example, Carley and Wainapel(Arch. Phys. Med. Rehabil. 66: 443-446, 1985 have shown that treatment of indolent ulcers with low density direct current significantly increased the healing rate of those treated individuals relative to individuals treated with conventional therapy, with a concomitant reduction in pain and discomfort in those treated with electrotherapy. Similarly, Biedebach, noting the "wound current" generated in damaged tissue in and also summarizing the overwhelming evidence of the healing properties of electrotherapy for ulcer treatment, proposed that enhancement of the natural current may be useful in accelerating the healing process.
There appears to be no doubt that the maintenance of an electric current on the skin is associated with the continued well-being of undamaged skin, and that application of a current to injured skin can be highly beneficial to the healing process of damaged skin. In addition to the reported treatment of ulcers, there are a number of other skin conditions involving irritation or inflammation which could also potentially benefit from preventive and/or therapeutic application of a low intensity current. However, the means for delivery of healing current to skin reported in the medical literature typically involve the use of machinery and monitoring which would be prohibitively expensive and complicated for the treatment of less serious skin disorders. It therefore would be desirable to have available a less intrusive, more cost-effective method of current delivery to the skin, which method could then benefit less life-threatening, but nonetheless painful and irritating, chronic and acute skin conditions, or simply to maintain the overall health of the skin. The present invention provides just such a method, which can be used routinely by the afflicted individual in an unmonitored home environment.